In the simplest quick connect tube couplings for connecting one tube to another or to a fluid vessel wall, there is typically a threaded fitting arrangement to connect the coupling to a vessel wall and a retainer arrangement separate from any such threaded fitting arrangement to retain the coupling connection whether the latter is tube-to-tube or tube-to-vessel. Moreover, there is without added parts or complexity no allowance or adjustment for large tolerances that would affect sealing. For example, in the simplest couplings, it is common practice to contain the O-ring seal in an axial direction with an upset bead on the end of the tube that is inserted into the coupling and to also provide tube retention with this bead using some form of flexible detent such as one or more spring arms that receive the tube bead with a snap fit. Typically, these prior couplings comprise separate parts for the different functions. Moreover, the simplest designs generally provide tube support in only one location such that side-to-side movement can occur causing changes in the O-ring compression.